1. Field of the Invention
This invention relates to a loudspeaker of moving coil type, particularly to an improvement in a loudspeaker of type wherein a voice coil bobbin is concentrically suspended by line within a gap of radial magnetic field.
2. Prior Art
Usually, in a loudspeaker having a diaphragm such as cone type, metal type or the like, there have been known as a damper supporting a voice coil bobbin attached to a diaphragm within a gap, for instance, a cloth damper which is impregnated with synthetic resin and concentrically molded by heat, a formed damper made of synthetic resin sheet, a line damper suspended by line and the like. Among such dampers, the line damper is recognized to be able to obtain good reproduced sound. However, as shown in U.S. Pat. No. 3,819,876, etc., the voice coil bobbin is suspended from three directions by three separate lines; therefore it is difficult to keep the tension of lines uniform and the operation is very hard to support the bobbin in a right position without being deformed. For such a reason, when a loudspeaker with a line suspended damper system is once operated, it is liable to cause troubles such that the bobbin is deformed and biased to the annular gap of the radial magnetic field, and because of difficulty in making uniform products, the quality control thereof is hard, thus this system has been hardly adopted by any maker for mass production.